An internal combustion engine, such as, for example, a compression ignition engine, spark ignition engine, or natural gas engine, may include a cylinder block defining at least one cylinder housing a reciprocating piston. The internal combustion engine may further include a crankshaft operably coupled to the piston, such that reciprocation of the piston within the cylinder serves to rotate the crankshaft. The crankshaft may be housed within a crankcase defined, for example, by a lower portion of the cylinder block and an oil pan. The crankcase may be adequately sealed from the surrounding atmosphere to prevent vapor from the engine from being expelled directly into the environment.
During an engine's operation, gases related to the combustion process may collect in the crankcase. Such gases may include, for example, oil mist particles and crankcase fumes (e.g., soot from combustion, unburned fuel, exhaust gases, and/or water vapor). These gases may contribute to pressure build-up within the crankcase, which may be undesirable for a number of reasons. In order to relieve this pressure build-up, the engine may include a crankcase ventilation system configured to vent a portion of these gases to the environment. In order to prevent venting of certain portions of the gases, the crankcase ventilation system may also serve to filter and retain oil mist particles. The retained oil mist particles may be collected and may be returned to the engine's lubrication system for reuse.
For example, U.S. Pat. No. 6,561,171 issued to Burgess on May 13, 2003 (“the '171 patent”), discloses a crankcase emission control system that includes a pair of filter elements for filtering oil from crankcase emissions. The system in the '171 patent also includes a sump and check valve system for returning the filtered oil to an engine. In the system of the '171 patent, crankcase emissions flow across the pair of filter elements in a horizontal direction. The '171 patent discloses that the sump collects oil coalescing on the downstream surface of the second filter and the collected oil is drained to the engine when the engine is idle or shut down.
Although the system disclosed in the '171 patent purportedly provides separation of oil from crankcase emissions, it requires the engine to be shut down or be in an idle state in order to drain oil back to the engine.
The systems and methods of the present disclosure may be directed towards improvements in the existing technology.